The present invention relates to a poly (trimethylene terephthalate) fiber, suited for use in clothing, which has excellent smoothness, abrasion resistance, cohesiveness and has an anti-static electricity property. The fiber also has good processability during various steps from the spinning step to the post-processing step, for example, during the spinning and drawing steps, unwinding step from yarn package, false-twist texturing, weaving, and knitting processings, and extremely good wound form of yarn package, thus providing a knitted/woven fabric having good quality such as elastic recovery, soft hand and homogeneity.
Poly(trimethylene terephthalate) (hereinafter abbreviated to xe2x80x9cPTTxe2x80x9d) obtained by polycondensing terephthalic acid or a lower alcohol ester of terephthalic acid represented by dimethyl terephthalate with trimethylene glycol (1,3-propanediol) is an epochal polymer having both properties which resemble those of polyamide, for example, excellent elastic recoverly, low elastic modulus (soft hand) and ease of dyeing, and properties which resemble to those of poly(ethylene terephthalate) (hereinafter abbreviated to xe2x80x9cPETxe2x80x9d), for example, light resistance, thermosetting property, dimensional stability and low water absorption. PTT has been applied to products such as clothing, BCF carpet, brushes and tennis gut due to the above-described features (Unexamined Patent Publication (Kokai) Nos. 9-3724, 8-173244 and 5-262862).
One of fibrous forms capable of employing the above-described properties of the PTT fiber as much as possible includes a false-twist textured yarn. The false-twist textured yarn of the. PTT fiber can serve as a markedly excellent raw yarn for stretch material because it is superior in elastic modulus and softness to known synthetic fibers, for example, polyester fiber such as PET fiber (Unexamined Patent Publication (Kokai) No. 9-78373).
On spinning and false-twist texturing of the polyester fiber represented by the PET fiber, it is essential to apply a finishing agent to the surface of the fiber. If the spinning and false-twist texturing are conducted without applying the finishing agent on the surface of the fiber, friction and static electricity increase to cause nap and yarn cutting, thus making it impossible to conduct industrial production. In the case where the false-twist texturing of the PET fiber is conducted, a finishing agent containing 70% by weight or more of a polyether prepared by copolymerizing polyoxyethylene with polyoxypropylene (hereinafter referred to as xe2x80x9cpolyetherxe2x80x9d) is usually applied to the surface of the fiber (e.g. Unexamined Patent Publication (Kokai) No. 63-57548). The reason is as follows. That is, since heating at 200xc2x0 C. or higher is required in the thermosetting step in the false-twist texturing of the PET fiber, it becomes necessary to use a finishing agent comprising a polyether, which is superior in heat resistance, as a principal component in order to inhibit staining of the heater caused by heat deterioration, although the friction coefficient increases.
With respect to a finishing agent for false twisting of the PTT fiber, an optimum composition has never been suggested, heretofore. The reason is as follows. That is, there has not been a method of preparing trimethylene glycol as a raw material of PTT until recently and an industrial study of production of the PTT fiber has never been made.
Considering the finishing agent for false twisting of the PET fiber, it may be supposed that the finishing agent for false twisting of the PET fiber can be used for the PTT fiber as it is because the PTT fiber and PET fiber resemble each other in chemical structure. As is apparent from the present inventors"" study, a finishing agent suited for the PTT fiber must be designed for the following two reasons. That is, (1) the PTT fiber and the polyester fiber other than the PTT fiber, which is represented by the PET fiber, differ drastically in physical properties of the fiber, in particular, the PTT fiber has a large friction coefficient and abrasive resistance, and (2) they differ drastically in optimum temperature conditions of the thermosetting step in the false-twist texturing step so that the thermosetting temperature of the PTT fiber must be set to a low temperature.
First, it will be shown that the PTT fiber has a large friction coefficient and abrasive resistance.
The PTT fiber exhibits such properties that the PTT fiber contracts easily to an original length when stretched like an elastic yarn because molecules of the PTT fiber bend largely in a Z-shape. Due to such elastic properties, when a single yarn is contacted with a roll, guide, hot plate or pin, or single yarns are contacted with each other in a state where a tension is applied in the spinning and processing step, the contact area increases, thereby to enhance the friction coefficient. When the spinning and drawing are continued in such a state, a nap is liable to occur. It has also been found that a nap of the fiber is liable to occur when the PTT fibers are rubbed with each other or the PTT fiber is strongly rubbed with the material other than the PTT fiber at the fiber side. It is assumed that such an ease of abrading depends on a Z-shaped bent molecular structure and that such a Z-shaped structure leads to reduction in an intermolecular force between adjacent molecules thereby to reduce a cohesive force acted in the intermolecular direction, thus deteriorating abrasion properties. On the other hand, the other polyester fiber, for example, PET fiber and poly (butylene terephthalate) fiber hardly exhibit elastic properties because its molecular chain is in the state of being extended to full length. The intermolecular cohesive force also tends to increase. Therefore, problems concerning friction properties and abrasion resistance of the PTT fiber hardly occur. If the finishing agent for false twisting of the PET fiber is applied to the PTT fiber, a polyether as a principal component of the finishing agent has a small effect of reducing the friction coefficient thereby to cause nap and yarn cutting. Therefore, the finishing agent for false twisting of the PET fiber can not be used industrially.
Next, it will be shown that the optimum temperature of the thermosetting step in the false-twist texturing step must be set to a lower temperature than that of the PET fiber.
As described previously, the thermosetting temperature in the false-twist texturing of the PET fiber exceeds 200xc2x0 C., but the PTT fiber cannot be thermally set at a temperature of 190xc2x0 C. or higher according to the present inventors"" study. The reason is as follows. That is, when the PTT fiber is heated to a temperature of 190xc2x0 C. or higher, the tenacity and elongation are drastically lowered and cutting of the fiber is liable to Accordingly, the thermosetting temperature of the PTT fiber in the false-twist texturing is usually within a range from 140 to 190xc2x0 C. Since the glass transition point of the PTT fiber is lower than that of the PET fiber even at a low thermosetting temperature, it becomes possible to conduct sufficient thermosetting. Accordingly, it is not necessary to secure the heat resistance at 200xc2x0 C. or higher in the finishing agent for false twisting of the PTT fiber so that it is not required to expressly use a finishing agent comprising a polyether component as a principal component, which has a poor effect of lowering the friction coefficient of the surface of the fiber.
As described above, a study on a finishing agent for false twisting and weaving/knitting, which is suited for the PTT fiber, has hardly been made. At present, a suggestion with respect to the necessity of design of a finishing agent in consideration of specific frictional abrasion properties of the PTT fiber and conditions of false twisting, and a means for solving the problem, have not been made.
Accordingly, the design of a finishing agent having a performance capable of solving problems due to the above-described specific properties of the fiber is indispensable to the industrial production of the PTT fiber.
Unexamined Patent Publication (Kokai) Nos. 4-24284 and 4-194077 suggest a finishing agent for PET, comprising a liquid aromatic hydrocarbon ester. However, even if this finishing agent is applied to the PTT fiber, the dynamic friction coefficient is not reduced and the occurrence of nap can not be inhibited.
With respect to the finishing agent of the PTT fiber, there is disclosed a technique of applying a surface treatment finishing agent comprising a silicone component or a Teflon component to a fishing line made of PTT (Unexamined Patent Publication (Kokai) No. 9-262046), though a fiber for clothing is not the subject of the finishing agent. However, there are drawbacks, that is, when using the finishing agent comprising a silicone component or a Teflon component as a principal component to the PTT fiber for clothing, it becomes difficult to remove the finishing agent during the scouring step of the fiber and the anti-static electricity property is lowered. Accordingly, only a product having poor feeling such as sliminess can be obtained from a cloth of the fiber using such a finishing agent.
As described above, no known technique suggests the design of the finishing agent, which is indispensable to solving of specific problems such as friction and abrasion in spinning and processing of the PTT fiber, particularly PTT fiber for use in clothing.
An object of the present invention is to provide a PTT fiber having excellent smoothness, abrasion resistance, cohesiveness and anti-static electricity property on which a finishing agent capable of solving problems of processability during the spinning and processing steps, that are caused by specific high abrasion coefficient and ease of abrading of the side of the fiber, is applied.
A more specific object of the present invention is to provide a PTT fiber on which an improved finishing agent is applied, which is capable of preparing a knitted/woven fabric having good quality such as elastic recovery, soft hand and homogeneity by enhancing processability during various steps from the spinning step to the post-processing step, for example, processability during the spinning and drawing steps, unwinding step from yarn package, false-twist texturing, weaving, and knitting processings.
An object of the present invention is attained by a polyester fiber having a birefringence of 0.025 or more, comprising at least 90% by weight of a poly (trimethylene terephthalate), on which a finishing agent comprising (1) an aliphatic hydrocarbon ester having a molecular weight of 300 to 800 and/or a mineral oil having a Redwood viscosity at 30xc2x0 C. of 40 to 500 seconds, (2) a polyether having a specific structure, (3) a nonionic surfactant, and (4) an ionic surfactant in a specific proportion is applied in a specific amount.
That is, the present invention is directed to a polyester fiber having a birefringence of 0.025 or more, comprising at least 90% by weight of a poly (trimethylene terephthalate), a finishing agent being applied on the surface of said fiber in the amount of 0.2 to 3% by weight, said finishing agent comprising, as an essential component, compounds (1) to (4):
(1) an aliphatic hydrocarbon ester having a molecular weight of 300 to 800 and/or a mineral oil having a Redwood viscosity at 30xc2x0 C. of 40 to 500 seconds, the content of which is 30 to 80% by weight based on the total amount of said finishing agent,
(2) a polyether having a structure represented by the following structural formula:
R1xe2x80x94Oxe2x80x94(CH2CH2O)n1xe2x80x94(CH(CH3)CH2O)n2xe2x80x94R2
(wherein R1 and R2 each represents a hydrogen atom or an organic group having 1 to 50 carbon atoms, and n1 and n2 each represents 1 to 1000), the content of which is 2 to 60% by weight based on the total amount of said finishing agent, said polyether containing an ethylene oxide unit and a propylene oxide unit, which are random-polymerized or block-copolymerized,
(3) a non-ionic surfactant which is at least one selected from a compound prepared by adding ethylene oxide or propylene oxide to an alcohol having 1 to 30 carbon atoms and a compound prepared by adding ethylene oxide and/or propylene oxide to a carboxylic acid, amine or amide having 5 to 30 carbon atoms, the number of moles of the total amount of oxides to be added being 1 to 100, the content of which is 5 to 40% by weight based on the total amount of said finishing agent, and
(4) an ionic surfactant, the content of which is 2 to 20% by weight based on the total amount of said finishing agent, the total amount of said compounds (1) to (4) being 80 to 100% by weight based on the total amount of said finishing agent.
The polyester fiber of the present invention is a polyester fiber having such abrasion properties that a fiber-fiber dynamic friction coefficient is from 0.3 to 0.45 and a fiber-metal dynamic friction coefficient is from 0.17 to 0.3, wherein spinning and processing properties are excellent and improved by using the above-described specific finishing agent.
The fiber-fiber dynamic friction coefficient is a parameter which shows the ease of causing a nap due to friction between the fibers. On the other hand, fiber-metal dynamic friction coefficient is a parameter which shows the ease of causing a nap due to rubbing between the fiber and the metal portion such as roll and hot plate.
When the fiber-fiber dynamic friction coefficient is smaller than 0.3, excess slip of the fiber occurs thereby to lower the spinning and drawing properties. On the other hand, when the fiber-fiber dynamic friction coefficient exceeds 0.45, the friction between the fibers becomes too large and a nap of the fiber is liable to occur. Furthermore, the fiber-metal dynamic friction coefficient is smaller than 0.17, excess slip of the fiber on the roll surface occurs thereby to lower the spinning and drawing properties. On the other hand, when the fiber-metal dynamic friction coefficient exceeds 0.3, the friction becomes too large and a nap is liable to occur.
The fiber-fiber static friction coefficient is a parameter which shows the quality of the wound form of a pirn or a cheese. When the fiber-fiber static friction coefficient is within a range from 0.27 to 0.4, there can be formed a pirn or cheese wherein the fiber has excellent shape and unwinding properties.
In the polyester fiber of the present invention, the above-described specific finishing agent is applied to the fiber having a birefringence of 0.025 or more. In the fiber having a birefringence of 0.025 or more, fiber surface molecules are securely oriented and, therefore, the fiber surface is securely coated with a finishing agent without excessively penetrating the finishing agent into the fibers, thereby making it possible to exhibit the performances of the finishing agent as much as possible.
In addition, the fiber having such a specified birefringence exhibits excellent elastic recovery because PTT molecules in the fiber are suitably oriented, and the resulting cloth also exhibits excellent elastic recovery. The polyester fiber other than PTT, for example, PET fiber does not exhibit excellent elastic recovery even if the birefringence is 0.025 or more. When the birefringence is 0.025 or less, molecules are liable to move easily because of poor orientation of the molecules. For this cause, fiber exhibits a low elastic recovery and becomes readily changed in properties under a slight change of temperature and load during storage or conveyance. In addition, since the applied finishing agent excessively penetrates into the fibers, properties of the finishing agent are deteriorated when the fibers are stored for a long period.
Since the PTT fiber is sufficiently oriented in a fiber having a birefringence of 0.05 or more, preferably from 0.05 to 0.1, its friction properties are not lowered during the weaving/knitting step, the false twisting step without drawing, and dyeing step.
Not only the polyester fiber having a birefringence of 0.025 to 0.05 is particularly suited for a fiber to be stretched and false-twist textured, but also the PTT molecules are suitably oriented, so that the properties of the fiber are not changed during the step of usual handling such as storage and transportation.
The polyester fiber of the present invention may be a multifilament or monofilament, or may be any of a short fiber and long fiber. The fineness of the polyester fiber of the present invention is not specifically limited, but is usually within a range from 5 to 200 d in terms of a total fineness and is usually within a range from 0.0001 to 10 d in terms of a single yarn fineness. The shape of the section includes, but is not limited to, a circular shape, a triangular shape, a flat shape and a star shape, and the fiber may also be a solid or hollow fiber.
The polymer constituting the polyester fiber of the present invention is made of PTT obtained by polycondensing 90% by weight or more of terephthalic acid with 1,3-trimethylene glycol. Within the range where the object of the present invention is not impaired, that is, 10% by weight or less, one or more other copolymers or polymers may be copolymerized and blended. The comonomer and polymer include, for example, oxalic acid, succinic acid, adipic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, ethylene glycol, butanediol, cyclohexanedimethanol, 5-sodium sulfoisophthalic acid, tetrabutyl phosphonium 5-sulfoisophthalate, polyethylene glycol, polybutylene glycol, polyethylene terephthalate, and polybutylene terephthalate.
If necessary, various additives, for example, delustering agents, thermal stabilizers, defoamers, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, crystal nucleating agents, and fluorescent whiteners may be copolymerized or mixed.
The birefringence of the polyester fiber of the present invention is 0.025 or more. When the birefringence is within the above range, the fiber exhibits an excellent elastic recovery because PTT molecules in the fiber are suitably oriented. The resulting cloth also exhibits an excellent elastic recovery. The polyester resin other than PTT, for example, PTT fiber cannot exhibit an excellent elastic recovery even if the birefringence is adjusted to 0.025 or more.
When the finishing agent in the present invention is applied to the PTT fiber having the birefringence of 0.025 or more, since the fiber surface molecules are securely oriented, the fiber surface is securely coated with the finishing agent without excessively penetrating into the fiber, thus making it possible to bring out the performances of the finishing agent as much as possible. When the birefringence is less than 0.025, the molecules move easily because of poor orientation of the molecules. Therefore, the finishing agent cannot be used for the purpose of the present invention because of low elastic recovery and change of properties of the yarn caused by a small change in temperature and application of load during the storage or transportation. Since the finishing agent applied excessively penetrates into the fiber, the properties of the finishing agent are impaired by storing for a long period. The fiber having the birefringence within a range from 0.025 to 0.05 is particularly suited for a fiber to be subjected to false-twin texturing with drawing. Since the PTT molecules are suitably oriented, the performances of the fiber having such a birefringence are not changed during a conventional handling process such as storage and transportation. However, the fiber exhibits excellent drawing, false-twist texturing and crimping properties in the drawing and false twisting steps. The fiber having the birefringence of 0.05 or more, preferably from 0.05 to 0.1, can be processed into a cloth through the weaving/knitting step, false twining step with no drawing, and dyeing step because the PTT fibers are sufficiently oriented.
The polyester fiber of the present invention comprises at least 90% by weight of PTT, and a birefringence of 0.025 or more and application of a finishing agent described below to the fiber make it possible to bring out performances of the PTT fiber such as excellent elastic recovery and soft hand as much as possible and to noticeably improve the processability from the spinning step to the false-twin texturing step. Thus, it becomes possible to bring out good qualities such as elastic recovery, softness and homogeneity for the woven/knitted fabric.
In the present invention, the finishing agent refers to an organic mixture to be applied to the surface of the fiber.
The finishing agent used in the present invention comprises, as essential components, compounds (1) to (4):
(1) an aliphatic hydrocarbon ester having a molecular weight of 300 to 800 and/or a mineral oil having a Redwood viscosity at 30xc2x0 C. of 40 to 500 seconds, the content of which is 30 to 80% by weight based on the total amount of said finishing agent,
(2) a polyether having a structure represented by the following structural formula:
R1xe2x80x94Oxe2x80x94(CH2CH2O)n1xe2x80x94(CH(CH3)CH2O)n2xe2x80x94R2
(wherein R1 and R2 each represents a hydrogen atom or an organic group having 1 to 50 carbon atoms, and n1 and n2 each represents 1 to 1000), the content of which is 2 to 60% by weight based on the total amount of said finishing agent, said polyether containing an ethylene oxide unit and a propylene oxide unit, which are random-polymerized or block-copolymerized,
(3) a non-ionic surfactant which is a compound prepared by adding ethylene oxide or propylene oxide to at least one selected from an alcohol, carboxylic acid, amine or amide having 1 to 30 carbon atoms, the number of moles of the total amount of oxides to be added being 1 to 100, the content of which is 5 to 40% by weight based on the total amount of said finishing agent, and
(4) an ionic surfactant, the content of which is 2 to 20% by weight based on the total amount of said finishing agent, the total amount of said compounds (1) to (4) being 80 to 100% by weight based on the total amount of said finishing agent.
[1] Compound (1)
The compound (1) as a first essential constituent component of the finishing agent is composed of an aliphatic hydrocarbon ester having a molecular weight of 300 to 800 and/or a mineral oil having a Redwood viscosity at 30xc2x0 C. of 40 to 500 seconds.
These aliphatic hydrocarbon ester and/or mineral oil are components required to improve the smoothness property of the PTT fiber thereby to reduce the friction coefficient. The aliphatic hydrocarbon ester includes, for example, various synthetic products and natural fats and oils. An aliphatic hydrocarbon ester as a synthetic product having a linear structure is particularly preferred to improve the smoothness property.
The aliphatic hydrocarbon ester as the synthetic product includes, for example, monoester, diester, triester, tetraester, pentaester and hexaester. In view of the smoothness property, monoester, diester and triester are preferably used. When the molecular weight of the aliphatic hydrocarbon ester is 300 or less, there arise problems that too low strength of the oil film causes easy removal of the ester from the surface of the fiber due to the guide and roll, resulting in lowering of the smoothness property of the fiber and that too low vapor pressure causes scattering of the ester in the step, resulting in a poor operation environment. When the molecular weight of the aliphatic hydrocarbon ester exceeds 800, the smoothness and sizing properties are lowered because of too high viscosity of the finishing agent, which is not preferred. The aliphatic hydrocarbon polyester having a molecular weight of 300 to 550 is a most preferred aliphatic hydrocarbon ester because of its particularly excellent smoothness property. Specific examples of the preferred synthetic product include isooctyl stearate, octyl stearate, octyl palmitate, isooctyl palmitate, 2-ethylhexyl stearate, oleyl laurate, isotridecyl stearte, oleyl oleate, dioleyl adipate and glycerin trilaurate. Of course, two or more aliphatic hydrocarbon esters may be used in combination. Octyl stearate, oleyl oleate, lauryl oleate and oleyl oleate are particularly preferred. Among these aliphatic hydrocarbon esters, an aliphatic hydrocarbon ester of a monohydric carboxylic acid and a monohydric alcohol is particularly preferred in view of molecular structure because it is superior in smoothness property. To enhance the heat resistance, an aliphatic hydrocarbon ester having a molecular weight of 400 to 800 is preferably used. In this case, a group wherein portion of hydrogen atoms may be substituted with a group containing a hetero atom such as oxygen atom and sulfur atom, for example, ether group, ester group, thioester group and sulfide group.
The mineral oil includes, for example, paraffinic, naphthenic and aromatic mineral oils. In view of an improvement in smoothness property, a paraffinic or a naphthenic mineral oil is preferably used. Of course, two or more mineral oils may be used in combination. As the mineral oil, for example, those having a Redwood viscosity at 30xc2x0 C. of 40 to 500 seconds are preferably used. The mineral oil having the Redwood viscosity less than 40 seconds is liable to be scattered and the effect may be lowered. When the mineral oil exhibits a Redwood viscosity of 500 seconds or more, the effect of improving the smoothness property is lowered because of high viscosity. The Redwood viscosity of the mineral oil is preferably from 50 to 400 seconds.
It is important to enhance the smoothness property that the content of the aliphatic hydrocarbon ester and/or mineral oil in the finishing agent in the present invention is from 30 to 80% by weight. When the content is less than 30% by weight, the smoothness property is poor. On the other hand, when the content is 80% by weight, the wound form of the pirn or cheese prepared by winding the fiber becomes poor because of too high a smoothness property. When using for false twisting, the content is preferably from 30 to 60% by weight. When using for weaving and knitting, the content is preferably from 50 to 70% by weight because a high smoothness property is required.
[2] Compound (2)
A second essential constituent component of the finishing agent is a polyether shown in the compound (2). The compound (2) serves to enhance the strength of the oil film formed on the surface of the fiber by the finishing agent, and is a component required to remarkably improve poor abrasion resistance as a drawback of the PTT fiber as a result of the addition of the component. Particularly, it exhibits such a noticeable effect that a nap of the fibers hardly occurs when the fibers are rubbed with each other during the spinning, drawing, false-twin texturing and weaving and knitting steps.
R1xe2x80x94Oxe2x80x94(CH2CH2O)n1xe2x80x94(CH(CH3)CH2O)n2xe2x80x94R2xe2x80x83xe2x80x83(2)
In the formula, R1 and R2 each represents a hydrogen atom or an organic group having 1 to 40 carbon atoms, and n1 and n2 each represents 1 to 1000. The organic group may be a hydrocarbon group, or portion or all of hydrocarbon groups may be substituted with a group or element containing a hetero atom, such as ester group, hydroxyl group, amide group, carboxyl group, halogen atom and sulfonic group. Preferably, hydrogen atom, R1 and R2 are aliphatic alcohol, aliphatic carboxylic acid, aliphatic amine and aliphatic amide residue, and the number of carbon atoms is preferably from 5 to 18. In the compound (2), an ethylene oxide unit and a propylene oxide unit may be random-polymerized or block-copolymerized. In case where a weight ratio of the propylene oxide unit to the ethylene oxide unit is from 20/80 to 70/30, the effect of inhibiting abrasion is high. More preferably, the weight ratio of the propylene oxide unit to the ethylene oxide unit is from 20/80 to 60/40. The molecular weight of the compound (2) is preferably from 400 to 20000, and particularly preferably from 1500 to 20000. In this case, a value corresponding to the molecular weight is employed as n, and n2. The molecular weight is particularly important. When the molecular weight is less than 400, the effect of inhibiting abrasion is small. On the other hand, when the molecular weight exceeds 20000, the static friction coefficient of the fiber is too reduced and the wound form tends to be bad. More preferably, the molecular weight is from 1500 to 15000. It is necessary that the content of the compound (2) in the finishing agent is from 2 to 60% by weight. When the content is less than 2% by weight, the effect of improving the abrasion resistance is small. On the other hand, when the content exceeds 60% by weight, the wound form is bad because of too low a fiber-fiber friction coefficient. When using for false-twin texturing, the content is preferably from 3 to 60% by weight, and particularly preferably from 5 to 40% by weight. When using for weaving and knitting, the content is preferably from 5 to 30% by weight.
[3] Compound (3)
A third essential constituent component of the finishing agent is a nonionic surfactant which is at least one selected from a compound prepared by adding ethylene oxide or propylene oxide to an alcohol having 1 to 30 carbon atoms and a compound prepared by adding ethylene oxide and/or propylene oxide to a carboxylic acid, amine or amide having 1 to 30 carbon atoms, the number of moles of the total amount of oxides to be added being 1 to 100, the content of which is 5 to 40% by weight based on the total amount of said finishing agent.
The nonionic surfactant is a component required to impart emulsifying property for properly emulsifying the respective components of the finishing agent, cohesiveness of fibers, application property of the finishing agent and abrasion resistance. The nonionic surfactant may have a linear or branched molecular structure or contain a plurality of functional groups. A portion or all of the hydrogen atoms may be substituted with a group or element containing a hetero atom, such as ester group, hydroxyl group, amide group, carboxyl group, halogen atom and sulfonic group.
The number of carbon atoms of the alcohol, carboxylic acid, amine and amide is from 1 to 30, preferably from 5 to 30 in view of the emulsifying property and cohesiveness, and more preferably from 8 to 18. The number of moles of ethylene oxide and propylene oxide added is from 1 to 100, and preferably from 3 to 15 in view of high smoothness property. In case where the ethylene oxide and propylene oxide coexist, they may be random-copolymerized or block-copolymerized.
Specific examples of the nonionic surfactant include polyoxyethylene stearyl ether, polyoxyethylene stearyl oleyl ether, .polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, monobutyl ether prepared by copolymerization of propylene oxide and ethylene oxide, polyoxyethylene bisphenol A dilaurate, polyoxyethylene bisphenol A laurate, polyoxyethylene bisphenol A distearate, polyoxyethylene bisphenol A stearate, polyoxyethylene bisphenol A dioleate, polyoxyethylene bisphenol A oleate, polyoxyethylene stearylamine, polyoxyethylene laurylamine, polyoxyethylene oleylamine, amide polyoxyethyleneoleate, amide polyoxyethylenelaurate, amide polyoxyethylenestearate, ethanolamide polyoxyethylenelaurate, ethanolamide polyoxyethyleneoleate, diethanolamide polyoxyethyleneoleate, amide diethylenetriamineoleate, polyoxypropylene stearyl ether, polyoxypropylene bisphenol A stearate, polypropylene stearylamine and amide polypropyleneoleate.
It is required to enhance the emulsifying property, cohesiveness of fibers, application property of the finishing agent and abrasion resistance that the content of these nonionic surfactants in the finishing agent is from 5 to 40% by weight. When the content is less than 5% by weight, the above performances are poor. On the other hand, when the content exceeds 30% by weight, a nap is liable to occur because of too high a friction. The content is preferably from 5 to 30% by weight.
[4] Compound (4)
A fourth essential constituent component of the finishing agent is an ionic surfactant. The ionic surfactant is a component required to impart the anti-static electricity property, abrasion resistance, emulsifying property and anti-corrosive property to the fiber.
As the ionic surfactant, any of an anionic surfactant, a cationic surfactant and an amphoteric surfactant may be used. The anionic surfactant is preferably used because the anti-static electricity property, abrasion resistance, emulsifying property and anti-corrosive property can be imparted. Particularly, a sulfonate salt compound, a phosphate and a higher fatty acid salt are preferred. Of course, two or more anionic surfactants may be used in combination. Specific examples of preferred ionic surfactant include the compounds (5) to (8) and these compounds are particularly superior in anti-static electricity property, abrasion resistance, emulsifying property and anti-corrosive property.
R5xe2x80x94SO3xe2x80x94X,xe2x80x83xe2x80x83(5)
(R6xe2x80x94Oxe2x80x94)P(xe2x95x90O)(OX)2,xe2x80x83xe2x80x83(6)
(R7xe2x80x94Oxe2x80x94)(R8xe2x80x94Oxe2x80x94)P(xe2x95x90O)(OX), andxe2x80x83xe2x80x83(7)
R9xe2x80x94COOxe2x80x94Xxe2x80x83xe2x80x83(8)
In these formulas, R1 to R9 each represents a hydrogen atom or an organic group having 4 to 40 carbon atoms. The organic group may be a hydrocarbon group, or portion or all of hydrocarbon groups may be substituted with a group or element containing a hetero atom, such as ester group, hydroxyl group, amide group, carboxyl group, halogen atom and sulfonic group. Preferably, it is a hydrocarbon group having 8 to 18 carbon atoms. X is an alkali metal or an alkali earth metal.
It is necessary to enhance the anti-static electricity property that the content of the nonionic surfactant in the finishing agent is from 2 to 20% by weight. When the content is less than 2% by weight, the anti-static electricity property, abrasion resistance, emulsifying property and anti-corrosive property are poor and the wound form is bad because of too low a fiber-fiber dynamic friction coefficient and too low a fiber-fiber static friction coefficient. On the other hand, when the content exceeds 20% by weight, a nap is liable to occur because of too high a friction. When using for false-twin texturing, the content is preferably from 2 to 15% by weight. When using for weaving and knitting, the content is preferably from 5 to 15% by weight.
It is necessary for the finishing agent containing the four above-described essential constituent components that the content of these four essential constituent components is within a range from 80 to 100% by weight based on the total amount of the finishing agent. Components for finishing agent may be contained in the finishing agent used in the present invention in the amount within the range where the object of the present invention is not inhibited, that is, less than 20% by weight. The components for a finishing agent are not specifically limited, but a silicone compound, for example, dimethylsilicone, a compound prepared by adding about 3 to 100 moles of ethylene oxide and/or propylene oxide to portion of methyl groups of dimethylsilicone through an alkyl group, and amine oxide having an organic group having 5 to 18 carbon atoms may be contained to improve the smoothness property and spreadability of the finishing agent over the fiber. To improve the antistatic electricity property, an imidazoline compound having a carboxylic acid metal salt unit may also be contained, in addition to the compound other than those defined in the present invention. The ester compound defined in the present invention, for example, an ester having an ether group may also be contained. Known antiseptics, anti-corrosive agents and antioxidants may also be contained. The content is preferably 10% by weight or less, and more preferably 7% by weight or less.
The finishing agent comprising the above constituent components can be applied to the fiber as an emulsion finishing agent without diluting, or after 5 to 60% by weight, preferably 5 to 35% by weight of the finishing agent was dispersed in water.
It is necessary that the amount of the finishing agent to be applied onto the fiber is from 0.2 to 3% by weight. When the amount is less than 0.2% by weight, the effect of the finishing agent is lowered. On the other hand, when the amount exceeds 3% by weight, the resistance of the fiber on running becomes too large and the finishing agent is adhered on the hot plate and guide to thereby contaminate them. When used for false-twist texturing, the content is preferably from 0.3 to 1.0% by weight, and particularly preferably from 0.3 to 0.6% by weight. When used for weaving and knitting, the content is preferably from 0.4 to 1.2% by weight, and particularly preferably from 0.5 to 1% by weight. Of course, a portion of the finishing agent may penetrate into the interior of the fiber.
The finishing agent used in the present invention can be applied to the fiber at any time as long as the spun yarn has been solidified after melt spinning of the polyester fiber of the present invention. Usually, the finishing agent is preferably applied before taking up. The spinning method, to which the finishing agent is applied, may be a method of drawing using a drawing machine after taking up an undrawn yarn, a method of preparing a semi-drawn yarn at 2000 to 4000 m/min and a high-speed spinning method of spinning and drawing at a spinning speed of 5000 to 14000 m/min. The birefringence of the polyester fiber of the present invention can be adjusted to 0.025 or more by spinning and drawing so that the extension of the resulting fiber is from 25 to 180%, preferably from 25 to 150%, and more preferably from 35 to 130%.
The fiber thus obtained is a fiber which satisfies both of the fiber-fiber dynamic friction coefficient of 0.3 to 0.45 and the fiber-metal dynamic friction coefficient of 0.17 to 0.3 and has good spinning properties and processability. The fiber-fiber dynamic becomes too large and a nap of the fiber is liable to occur. The fiber-metal dynamic friction coefficient is preferably from 0.3 to 0.23.
Furthermore, when the fiber-fiber static friction coefficient is within a range from 0.27 to 0.4, a more preferred fiber is obtained. Since the fiber-fiber static friction coefficient corresponds to the amount of polyether, both good abrasion resistance and wound form can be attained by controlling the amount of polyether thereby to adjust the fiber-fiber static friction coefficient within arrange from 0.27 to 0.4. The fiber-fiber static friction coefficient is a parameter which shows the quality of the wound form of a pirn or a cheese. When the fiber-fiber static friction coefficient is less than 0.27, the wound form is not retained because of a too-small fiber-fiber static friction coefficient. On the other hand, when the fiber-fiber static friction coefficient exceeds 0.4, a fiber having a high friction coefficient is obtained and the processability is lowered. The fiber-fiber static friction coefficient is preferably within a range from 0.28 to 0.35.
The polyester fiber of the present invention exhibits the following physical properties of the fiber.
The tenacity of the polyester fiber is preferably 3 g/d or more in the case of a drawn yarn, while it is preferably 1.0 g/d in the case of a semi-drawn yarn. When the strength is less than 3 g/d in the case of the drawn yarn, the tear strength and burst strength of the resulting cloth are reduced depending on the use. The strength is preferably 4 g/d or more.
The elongation of the polyester fiber of the present invention is usually from 25 to 180%. When the elongation is less than 25%, the abrasion property of the fiber is drastically lowered and the abrasion property becomes poor even if the finishing agent described below is applied to the fiber, thereby making it difficult to apply it to practical use. On the other hand, when the elongation exceeds 180%, orientation of the fibers becomes poor and the fiber easily may cause the change of properties due to a slight change in temperature and application of weight. In order to preferably use as a drawn yarn, the elongation is preferably from 35 to 55% to inhibit the occurrence of nap, while the extension is preferably from 40 to 130% to use as a semi-drawn yarn to be stretched and false-twined.
The elastic recovery at 20% extension of the polyester fiber according to the present invention is preferably 70% or more. By satisfying the elastic recovery, the resulting cloth has a markedly excellent stretching property. The elastic recovery at 20% extension is preferably 80% or more.
The elastic modulus of the polyester fiber of the present invention is within a range from 10 to 30 g/d. Such a low elastic modulus leads to a cloth having markedly sot hand. The elastic modulus is preferably from 20 to 25 g/d.
The intrinsic viscosity [xcex7] of the polyester fiber according to the present invention is preferably from 0.4 to 2.0, particularly preferably from 0.5 to 1.5, and more preferably from 0.6 to 1.2. When the intrinsic viscosity is within the above range, a fiber having excellent strength and spinning property can be obtained. When the intrinsic viscosity is less than 0.4, the melt viscosity of the polymer is too small so that spinning becomes unstable and the strength of the resulting fiber is low, which is not satisfactory. On the other hand, when the intrinsic viscosity exceeds 2.0, melt fracture and poor spinning occur on spinning because of too large a melt viscosity.